Can’t sleep

Why can’t I sleep? I try to sleep but voices in my head are always fucking talking and it’s making me so frustrated. Why is this? I try to go to bed early, it happens, so then I end up laying there for ages and not being able to sleep. It takes me forever to finally block the voices out. It sound like I’m insane , but it’s like the voices of my thoughts or a song will be getting sung over and over, or I’ll review my whole fucking day , or random things that are irrelevant. Why are these voices here and why can’t I stop them